This indicator is designed to accompany the SHMI data at site of treatment level.
The SHMI is calculated at the level of the provider spell, which is a continuous period of time spent as a patient within a single trust (provider). A spell may be composed of more than 1 episode (a single period of care under 1 consultant). If a patient is moved between hospitals or sites within the same trust, the provider spell continues. Most spells consist of a single episode and so there is no complication when presenting SHMI data at site level because the entire provider spell occurred at a single site.
However, spells consisting of multiple episodes may have occurred over multiple sites and only 1 of these sites can be associated with the spell. This has been chosen to be the site of the 1st episode in the spell. This may result in hospital deaths being attributed to a site other than the one in which they occurred, with an impact on the SHMI values presented for the sites concerned. This impact is likely to be greater for sites within trusts showing higher percentages for this contextual indicator.
Notes:
1. There is a shortfall in the number of records for Barking, Havering and Redbridge University Hospitals NHS Trust (trust code RF4), Buckinghamshire Healthcare NHS Trust (trust code RXQ), East Suffolk and North Essex NHS Foundation Trust (trust code RDE), Mid Cheshire Hospitals NHS Foundation Trust (trust code RBT), Sheffield Teaching Hospitals NHS Foundation Trust (trust code RHQ), and The Shrewsbury and Telford Hospital NHS Trust (trust code RXW). Values for these trusts are based on incomplete data and should therefore be interpreted with caution.
2. On 1st April 2026, Bridgewater Community Healthcare NHS Foundation Trust (trust code RY2) was acquired by Warrington and Halton Teaching Hospitals NHS Foundation Trust (trust code RWW). The new organisation is called North Cheshire and Mersey NHS Foundation Trust (trust code RWW). Bridgewater Community Healthcare NHS Foundation trust does not submit activity to HES APC so the impact on the SHMI is minimal, although mapping their data to the new trust, for completeness, will be done at a later date.
3. A number of trusts are now submitting Same Day Emergency Care (SDEC) data to the Emergency Care Data Set (ECDS) rather than the Admitted Patient Care (APC) dataset. The SHMI is calculated using APC data. Removal of SDEC activity from the APC data may impact a trust’s SHMI value and may increase it. More information about this is available in the Background Quality Report.
4. Further information on data quality can be found in the SHMI background quality report, which can be downloaded from the 'Resources' section of this page.